Taking responsibility for another human life is a familiar duty for veterans, Covino says.

"To have been in situations where they've needed to rely on judgment and develop a capacity for reflection, an ability to act autonomously and courageously. ... Those are qualities of character you can't teach," Covino said.

"They haven't experienced it"

Jon Neely, a 45-year-old living in Springfield, Illinois, has been using Vets Prevail for several months and says he logs on for about an hour every week, though when he first began using it, he logged on every day. Neely served in Kosovo from 1999 to 2000 and retired from the military in 2005.

"All too often, you go seek help from somebody that is book-learned, but they don't understand," he said. "They don't know. To me, getting help or seeking help from a non-veteran is like going to a marriage counselor that has never been married. They know all the book knowledge, but they haven't experienced it."

Sarah Bonner, 31, an Air Force veteran who was medically discharged from Ramstein Air Base in Germany in 2006, is an active user of Vets Prevail. She says that talking to a "like-minded" person is what has kept her coming back to the site.

She has bonded with the peer coaches, to whom she refers by their first names like friends, in a way she did not expect.

"There were a couple times recently, I was at a really low point," she said. "I was angry, and I wasn't holding back with what I said. They don't care. If I want to cuss out and threaten to punch something, they might say, 'Let's think of softer things than the wall to punch.' ... They let you talk about the stuff that's ugly."

"Why did all of us serve?"

Training veterans to treat other veterans does involve some risk, Chester says. If veterans are not stable themselves, they should not treat others as mental health professionals. For that reason, it can be a good idea for them to work with a psychologist even while they administer care to others.

There is so much training and hands-on experience involved in a post-doctorate program that it is highly unlikely a veteran who is still feeling unstable would make it all the way through, Troiani says. Rarely, but occasionally, a veteran will say, "This program is not a good fit for me," he says.

But if it is a good fit, the results can be rewarding.

"Why did all of us serve if not for each other?" Kyle asked. "Just because we're not in the military any more, it doesn't mean we are no longer brother and sister. It's a bond we'll have for the rest of our lives."